Each year the transportation industry loses millions of dollars through tire pilferage and tire theft. Many companies experience difficulty with the so called "tire swap outs" wherein a driver exchanges the tires on his truck for older or inferior tires and some cash. It is an object of this invention to provide a reliable tamper indicator so that one can easily detect when the tires on a vehicle have been removed or tampered with. A second objective of this invention is to deter tire thieves.
Many of the prior devices designed to prevent tire theft operate on the principle of a lock which is removable only with a special key. Of course, the driver of the vehicle must necessarily carry a copy of the lock key with him so that he may repair a flat or damaged tire. Since a person with the key can easily remove the tire without leaving any indication that any tampering had taken place, these devices are ineffective as tamper indicators.
Other prior art devices use a break-off nut which is connected to a smooth surfaced fastening nut. The break-off nut is broken away from the fastening nut when it is tightened beyond a certain torque level. Removal of the fastened object is thereby rendered more difficult or impossible because the rounded surfaces of the fastening nut cannot be gripped by a conventional wrench. Prior art devices of this type require specially machined fasteners. In addition, the torque requirements of the fastening nut must be determined for each application so that the break-off nut can be designed accordingly. Furthermore, these prior art devices are impractical because they are extremely difficult to remove once the breakable fastener has been sheared off. This makes needful tire replacement very difficult.